90% of the time its an emotional response, not dietary. It could be Pookey honestly, you said yourself he is unpredictable. Or it could be any new thing in the environment. Try switching cage placement, different toys, putting furniture in different spots. My Gray doesnt like anything like coat hangers brooms stuff like that, she is very sensitive to certain things around her. You can also try playing soothing music around Cleo, our gray "Onyx" she definately reacts to music. She actually has her own radio and her favorite song.Just play around with things, see what happens. Worth a try. Good Luck!